A fuse is widely used by many circuits or systems to protect them from short circuit, overcurrent or overheating. The traditional fuse is based on the principle of reducing the cross-section area of a material with a high melting point so that the reduced cross-section area breaks before a peak value of a short circuit current arrives.
Current circuits or systems have more strict requirements for their protection, for example, the circuits or systems used in electric automobiles. In the electric automobile it may be required for the power battery to store a large amount of electric energy. As a result the power battery works under an environment of high temperature and strong vibrations. An electric automobile often works under an uncertain road condition as well as the potential threat of traffic accidents, so it is very important to protect the power battery from short circuit.
Because of the above factors, a quick fuse may be adopted by a battery module. The theory of the quick fuse is to reduce the conductive area of a fuse having a high melting point. Under normal working condition, the reduced conductive area does not break because of a balance among the thermal power, the heat exchange and the heat radiating power. But when short circuit occurs, the instant current may be so large that a large amount of heat is instantly produced at the reduced conductive area such that the heat does not dissipate fast enough, causing the reduced conductive area to melt instantaneously to cut off the circuit before the peak value of the short circuit current arrives.
But the traditional quick fuse has the following problems: high resistance; too fast response time that may cause the fuse to accidentally break; weak endurance which may not endure the high peak value of a pulse current. For example, in a pulse current heating system of an electric automobile, the peak value of the current may be too great for the traditional quick fuse.